An effective manual deboning method to prepare intact mouse nasal tissue with preserved anatomical organization.
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The mammalian nose is a multi-functional organ with intricate internal structures. The nasal cavity is lined with various epithelia such as olfactory, respiratory, and squamous epithelia which differ markedly in anatomical locations, morphology, and functions. In adult mice, the nose is covered with various skull bones, limiting experimental access to internal structures, especially those in the posterior such as the main olfactory epithelium (MOE). Here we describe an effective method for obtaining almost the entire and intact nasal tissues with preserved anatomical organization. Using surgical tools under a dissecting microscope, we sequentially remove the skull bones surrounding the nasal tissue. This procedure can be performed on both paraformaldehyde-fixed and freshly dissected, skinned mouse heads. The entire deboning procedure takes about 20-30 min, which is significantly shorter than the experimental time required for conventional chemical-based decalcification. In addition, we present an easy method to remove air bubbles trapped between turbinates, which is critical for obtaining intact thin horizontal or coronal or sagittal sections from the nasal tissue preparation. Nasal tissue prepared using our method can be used for whole mount observation of the entire epithelia, as well as morphological, immunocytochemical, RNA in situ hybridization, and physiological studies, especially in studies where region-specific examination and comparison are of interest. (+info)
Ultrastructure, morphology and organization of biogenic magnetite from sockeye salmon, Oncorhynchus nerka: implications for magnetoreception.
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Although ferromagnetic material has been detected in the tissues of a variety of animals that are known or suspected to respond to magnetic fields, in only a few cases has the material been identified and its suitability for use in magnetoreception been determined. Using high-resolution transmission electron microscopy (HRTEM), we have studied magnetic particles isolated from ethmoid tissue of the sockeye salmon, Oncorhynchus nerka. Low-magnification electron micrographs showed chains containing up to 58 (median = 21-25) electron-dense particles that were held together by intimately attached organic material. The particle size range was 25-60 nm with a mean of 48 nm and a standard deviation of 8.5 nm. Elemental analysis, by energy-dispersive X-ray analysis (EDXA), electron diffraction patterns and HRTEM lattice images, showed that many of the particles were structurally well-ordered and crystallographically single-domain magnetite. These results imply that the production of the biomineral is under precise biological control. The crystal morphology was cubo-octahedral with the (111) faces of adjacent crystals lying perpendicular to the chain axis. The magnetic moments of the particles will therefore be aligned along the chain axis and will sum to produce a total moment dependent on the number of particles present in each chain. In the presence of the geomagnetic field, the mean moment for the particles will give a magnetic to thermal energy ratio of about 0.2. The corresponding calculations for individual chains gave two clusters of ratios ranging between 2.7 and 5.3 and between 6.6 and 9.5. The implications of these results in the possible use of the particles in magnetoreception are discussed. (+info)
Production of single-domain magnetite throughout life by sockeye salmon, Oncorhynchus nerka.
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Although single-domain particles of biogenic magnetite have been found in different species of pelagic fishes, nothing is known about when it is synthesized, or about whether the time during life when it is produced is correlated with the development of responses to magnetic field stimuli. We have investigated production of biogenic magnetite suitable for use in magnetoreception in different life stages of the sockeye salmon, Oncorhynchus nerka (Walbaum). Sockeye salmon were chosen because responses in orientation arenas to magnetic field stimuli have been demonstrated in both fry and smolt stages of this species. We found significant quantities of single-domain magnetite in connective tissue from the ethmoid region of the skull of adult (4-year-old) sockeye salmon. The ontogenetic study revealed an orderly increase in the amount of magnetic material in the same region of the skull but not in other tissues of sockeye salmon fry, yearlings and smolts. The physical properties of this material closely matched those of magnetite particles extracted from the ethmoid tissue of the adult fish. We suggest that single-domain magnetite particles suitable for use in magnetoreception are produced throughout life in the ethmoid region of the skull in sockeye salmon. Based on theoretical calculations, we conclude that there are enough particles present in the skulls of the fry to mediate their responses to magnetic field direction. By the smolt stage, the amount of magnetite present in the front of the skull is sufficient to provide the fish with a magnetoreceptor capable of detecting small changes in the intensity of the geomagnetic field. Other tissues of the salmon, such as the eye and skin, often contained ferromagnetic material, although the magnetizations of these tissues were usually more variable than in the ethmoid tissue. These deposits of unidentified magnetic material, some of which may be magnetite, appear almost exclusively in adults and so would not be useful in magnetoreception by young fish. We suggest that tissue from within the ethmoid region of the skull in pelagic fishes is the only site yet identified where magnetite suitable for use in magnetoreception is concentrated. (+info)
Epidemiology of frontoethmoidal encephalomeningocoele in Burma.
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One hundred and thirty nine patients suffering from encephalomeningocoele and myelomeningocoele who had attended the neurosurgical outpatients department of the Rangoon People's Hospital were interviewed. A predominance of frontal encephalomeningocoele was found; a low proportion of these patients had been conceived in the cold season and an increased interval separated the index patients from the previous full term pregnancy of their mothers; no first degree relatives were affected. It is suggested that an environmental factor is implicated in the developmental aetiology. (+info)
New perspectives in the management of severe cranio-facial deformity.
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It is postulated that craniosynostosis is due to a growth abnormality in all or part of the cranial capsule. Release of the stenosed part in the first months of life will re-establish the balance between the rapidly growing brain and eye, and the cranial capsule. Three periods for operative treatment are described: early, intermediate and late. Only in the early period can operative treatment restore normal growth dynamics; in the late period the aim is correction of an established deformity. The relationship between cranial clefts and frontonasal encephaloceles is explored. If the space-occupying encephalocele is removed early, the distorted facial bones adopt a more normal position, whereas cranial clefts do not respond to early operation by remoulding. The treatment of the acquired deformities of acute cranio-facial trauma have taken on new perspectives with the application of the multi-disciplinary approach and surgical techniques developed in the treatment of congenital deformities resulting in considerable reduction in the period of hospitalisation. (+info)
Basal encephalocele and morning glory syndrome.
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Basal encephaloceles are often associated with other midline anomalies such as hypertelorism, broad nasal root, cleft lip, and cleft palate. Optic disc anomalies such as pallor, dysplasia, optic pit, coLoboma, and megalopapilla have been reported to occur in patients with basal encephalocele We report a case of a child with a sphenoethmoidal encephalocele and morning glory syndrome of the optic nerve. The presence of such optic nerve anomalies with facial midline anomalies should alert the clinician to the possible presence of a basal encephalocele. (+info)
Fibro-osseous lesions of the jaw: a review of 133 cases from Nigeria.
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A review of 133 cases of fibro-osseous lesions seen and treated at the University College Hospital, Ibadan, Nigeria, is presented. The age of patients at time of diagnosis ranged from 4 years to 68 years, although over 56 percent occurred in the first two decades of life. The maxilla was more commonly affected and there was a female preponderance in the incidence. Radical surgery was often indicated and performed because of the extent of lesions when presented. Early attempts at graft reconstructions were largely abandoned because of high failure rates. Tumor recurrences or growth cessations were not predictable as some lesions regressed after minor interventions while others grew rather rapidly following radical surgery. (+info)
Cerebrospinal fluid rhinorrhoea in pituitary tumours.
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Three cases of CSF rhinorrhoea due to pituitary tumours are reported and the literature reviewed. The treatment of choice appears to be trans-sphenoidal exploration of the pituitary fossa with insertion of a free muscle graft followed by radiotherapy. The probability of the tumour being a prolactin-secreting adenoma is discussed. (+info)